Gold-Selenide Separation

[Reno Chris]

You were missed.

Thanks. Just been busy. About to head for Africa to teach Africans about finding gold with a metal detector (for the second time in the last year).

 

[omzimm]

Gold will dissolve in one acid, selenic acid. Roasting with sodium nitrate and sodium carbonate or sodium hydroxide will make the selenium dissolve in water. When using chemicals be carful.

 

[omzimm]

The big boys use a sodium hydroxide and sodium nitrate melt on ores containing precious metals and selenium. Then water leaching the melt to dissolve selenium. Sample 30 grams-Sodium hydroxide30 grams- 25% to 50% of sample weight sodium nitrate, heat at 250-400 degrees C for two hours then leach. with di water. If the precious metals are mixed with the rare earths then they will dissolve in HCL solution and can be precipitated with oxalic acid. Remember that most forms of selenium, selenite and selenate when mixed with acids produce selenic acid and it is well known that selenic acid will dissolve gold. Most large copper mines use this method to extract the selenium. I hope his will help. Aways be careful when using chemicals Have a good day OZ..